A Test for Cobalt

Abstract

Dimethylglyoxime was used by Braley and Hobart ¹ as an analytical reagent for cobalt following the researches of Tschugaeff ² on metallic derivatives of dioximes. Compounds containing ammonia or pyridine were studied, and the brown colorations permitted to detect as little as 5 γ of cobalt. Using the same reagent combined with alkaline sulfides, Feigl and von Tustanowska ³ obtained a violet red coloration which allowed them to detect cobalt ion in a dilution of 1 to 830000. Bertrand and Machebeuf ⁴ developed a colorimetric method for the determination of cobalt in biological materials. Charottino ⁵ replaced ammonia by certain amines, chiefly aromatic ones (benzidine), and claimed to have thus increased the sensitivity of the test, which was confirmed by Braun ⁶. Finally, by the use of toluidine, Spacu and Macaronici ⁷ attained a still higher sensitivity.